Because nobody respects mechanics. Not customers, not managers, not even other mechanics. I can’t tell you how often someone will walk right into a shop and start talking to a mechanic working on a car. The sheer stupidity of that is lost on someone, yet they would never dream of going to a restaurant, walking right into the kitchen and telling the cook what he wants for dinner.
“Hey Joe, this lady has a question about the brake job you did yesterday.” “I’m busy doing this oil change. She can wait.” “No, she’s a good customer and she’s in a hurry, come talk to her.”
“Hey Joe, give me a hand here, this transmission’s falling off the jack, I’m gonna lose it!!” “Yeah, I’ll be there as soon as I finish this oil change.” “Now dammit, I need help!”
I don’t eat at McDonalds regularly, but I’ve noticed that the order from the drive-thru window is occasionally wrong. A kid starting out working part-time at McDonalds can make more per hour than a kid starting out at QuickyLubeOilMartExpress. So I would imagine that the success rate at McDonalds would be higher than the success rate at LubeBay, based solely on the workers it can draw based on pay. So yes, it can be that simple, as you imply above. You can only train a monkey to do so much. Oil changers are entry-level. We need to weed out the idiots to see who might actually be able to fix a car one day. And the lube rack is where that happens. I don’t like it, but I can’t change an industry.
You want to make sure that your car is serviced by a thorough, experienced, qualified professional? Then pay for it. A $35 oil change gets you a monkey with a crescent wrench. Double that price, you might get some quality.
But that’s not to say that what happened to the RAV4 driver is because of those things. The drain plug simply wasn’t tightened properly. That’s going to happen from time to time. I don’t car who you are or what you do, at some point in your career, in the course of doing your job, you’re going to make a mistake. I make a mistake, a wheel comes off a car. My wife makes a mistake at her job, someone’s payroll isn’t processed on payday. A doctor makes a mistake, my brother has a forgotten drainage tube festering in his abdomen. An engineer makes a mistake, an airplane crashes. It’s as simple as that.
An average mechanic works on 25 cars a week. Suppose he has a 99% perfection rate (who in any job has that?) That leaves one car per month with which something goes wrong. Maybe the RAV4 was that one.